Wednesday, January 20, 2016

'Planet X' now 'Planet Nine?'

There
may be a ninth planet in the solar system, after all. Earlier today,
it was announced by astronomer Mike Brown of Caltech, among others, that there might be a planet 10 times more massive
than earth orbiting the Sun in the far-off Kuiper Belt at a distance
more than 20 times farther than Neptune. The existence of this dark,
far-away world was hypothesized by analyzing irregularities in the
orbits of distant Kuiper Belt objects, which seem to suggest that
there is interaction with some large, as-yet unseen body.

For, Brown, this finding would be both ironic and
vindicating as Brown was the astronomer who discovered Sedna, the
body Brown initially believed to be the 10th planet at
discovery. 30% more massive than Pluto but over 3 times more
distant, Sedna never held the status of 'planet' despite being bigger
than Pluto. Why? When it was discovered in 1930, Pluto was thought to
be alone. By 2005, Sedna was known to be one of hundreds of Kuiper
Belt objects (KBOs), which raised a question: how could the bigger of
the two bodies not be a planet while the smaller one was a planet?
End result: the word 'planet' was defined for the first time, Pluto
was demoted to 'dwarf planet,' and Neptune became the outermost
planet in the solar system.

Fast-forward
16 years.

This
hypothetical Planet Nine, if confirmed, is no dwarf based upon the
evidence being used to make a case for its existence.

According
to the research paper,
six KBOs orbit the sun on elliptical paths that all point in the same
direction. The kicker that provides evidence for a massive planet?
All six bodies are moving at different speeds and they all share the
same tilt, roughly 30 degrees down relative to the ecliptic plane, on
which all 8 planets orbit the Sun. According to the scientists, the
odds of this occurring by random chance is 7/1000.

Additionally,
the team used other possibilities to explain the orbits of these 6
oddball KBOs, namely interactions with other KBOs. In the end, such
calculations didn't match up with the observations, but when the
numbers for a 10-Earth mass planet were put into the equation, the
model worked much better. In addition, the existence of such a large
body could also explain orbital oddities in Brown's Sedna and another
large KBO, 2012VP113.

In
speaking to the press, Brown said that not only did Planet Nine kill
two birds (the 6 oddball KBO orbits and oddities for Sedna and
2012VP113) with one stone, but also a third that they didn't even
know about, namely the absence of a between Earth and Neptune-size
planet, now known to be the most common size in the cosmos, in our
own solar system.

As
of now, the orbit for this hypothetical planet has been calculated
and the hunt is on to spot it visually. Brown has said that he would
like to be the first to make visual confirmation but will be okay if
another team beats him to it because this finding could be the
impetus for a whole new generation of planet finders to go to the
telescopes and begin searching the skies.

Hopefully,
someone will visually confirm this planet's existence sooner rather
than later.